The influence of interferences on response of the new potentiometric sensor for anionic surfactant determination

Tenzidi su površinski aktivne tvari koje se sastoje od hidrofilnog i hidrofobnog dijela. Dijele se na anionske, kationske, neionske i amfolitske tenzide. Anionski tenzidi su najzastupljeniji i najčešće se koriste u obliku praškastih detergenata jer lako uklanjaju mrlje sa odjeće. Osjetljivi su na tvrdoću vode. Tenzidi se mogu analizirati titracijskim, spektrofotometrijskim i kromatografskim metodama te metodom injektiranja u protok. Određivanje završne točke titracije i analiza tenzida najčešće se provode potenciometrijskim titracijama koje koriste tenzidno-selektivne elektrode. Membrana koja je korištena za određivanje utjecaja interferenata na odziv elektrode sadrži ionski par dimetildioktadecilamonijev-tetrafenilborat (DMDODA-TPB). Mjeren je odziv na natrijev dodecilsulfat (NaDDS) koncentracije 5 x 10- 4 mol/dm3. Ispitan je utjecaj nekoliko interferenata na odzivne karakteristike NaDDS-a. Kao interferenti korišteni su: natrijev sulfat (Na2SO4), natrijev acetat (CH3COONa), natrijev hidrogensulfat monohidrat (NaHSO4 × H2O), natrijev karbonat (Na2CO3) i natrijev hidrogenkarbonat (NaHCO3) koncentracija 1×10-2 mol/dm3.Surfactants are surface active agents consisting of a hydrophilic and hydrophobic part. They are divided into anionic, cationic, nonionic and ampholytic surfactants. Anionic surfactants are the most common and most widely used in the form of powder detergents as easy to remove stains from clothing. They are sensitive to water hardness. Surfactants can be analyzed by titration, spectrophotometric, chromatographic and flow injection method. Determination of the equivalence point titration and analysis of surfactants are usually carried out by potentiometric titration using surfactant-selective electrode. The membrane that was used to determine the influence of interfering substances on the response of the electrode contains an ion pair dimethyldioctadecylammonium-tetraphenylborate (DMDODA-TPB). The response to sodium dodecyl sulfate (NaDDS) concentrations of 5 x 10-4 mol/dm3 was measured. The influence of a number of interfering substances on the response characteristics of NaDDS was tested. Sodium sulfate (Na2SO4), sodium acetate (CH3COONa), sodium hydrogen sulfate monohydrate (NaHSO4 × H2O), sodium carbonate (Na2CO3) and sodium hydrogen carbonate (NaHCO3) with concentrations of 1 × 10-2 mol/dm3 were used as interfering substances